21181-44-2Relevant academic research and scientific papers
Preparation and reaction chemistry of novel silicon-substituted 1,3-dienes
Choudhury, Partha P.,Welker, Mark E.
, p. 16892 - 16907 (2015/12/01)
2-Silicon-substituted 1,3-dienes containing non transferrable groups known to promote transmetallation were prepared by Grignard chemistry and enyne metathesis. These dienes participated in one pot metathesis/Diels-Alder reactions in regio- and diastereoselective fashions. Electron-rich alkenes showed the fastest rates in metathesis reactions, and ethylene, a commonly used metathesis promoter slowed enyne metathesis. 2-Pyridyldimethylsilyl and 2-thienyldimethylsilyl substituted Diels-Alder cycloadducts participated in cross-coupling chemistry and the 2-thienyldimethylsilyl substituted cycloadducts underwent cross-coupling under very mild reaction conditions.
Preparation of 2-BF3-substituted 1,3-dienes and their Diels-Alder/cross-coupling reactions
De, Subhasis,Welker, Mark E.
, p. 2481 - 2484 (2007/10/03)
(Chemical Equation Presented) 2-BF3-substituted 1,3-butadienes with potassium and tetrabutylammonium counterions have been prepared in gram quantities from chloroprene via a simple synthetic procedure. The potassium salt of this new main group element substituted diene has been characterized by 1H, 13C, 11B, and 19F NMR. Diels-Alder reactions of these dienes with ethyl acrylate and methyl vinyl ketone are reported, as well as subsequent Pd-catalyzed cross-coupling reactions of those Diels-Alder adducts.
Ring enlargement reaction of 2-(1-alkenyl)-1-cyclobutyl ketones. A new method for the preparation of 4-acyl-1-cyclohexenes
Fujiwara, Tooru,Takeda, Takeshi
, p. 6027 - 6030 (2007/10/02)
Various 1,2-disubstituted 4-acyl-1-cyclohexenes were obtained by the ethylaluminum dichloride promoted ring enlargement reaction of 2-(1-alkenyl)-1-cyclobutyl ketones prepared by the conjugate addition of 1-alkenylmagnesium bromides With 1-cyclobutenyl ketones.
A Formylation-Cyclization Method of Synthesis of Cycloalkenones from Unsaturated Ketones. 2. Simple Synthesis of Some Functionalized Bicyclononane Derivatives
Chakraborti, Ratna,Ranu, Brindaban C.,Ghatak, Usha Ranjan
, p. 5268 - 5271 (2007/10/02)
The potential generality of formylation-cyclization of a variety of γ,δ-unsaturated methyl ketones as a route to some functionalized bicyclononane derivatives has been examined.Thus, perchloric acid catalyzed reactions of β-diethoxyethyl ketones 2a-c and 14a-c, derived from the 2-acetyl-2-methylhexahydrophenanthrenes and tetrahydrofluorenes 1a-c and 13a-c, respectively, in the absence and presence of triethyl orthoformate, afforded the corresponding bridged dienones 3a-c and 15a-c and enones 4a-c and 16a-c in excellent yields.The bridged enones 4a-c and 16a-c are also formed by direct reaction of the methyl ketones 1b,c and 13a-c with triethyl orthoformate and perchloric acid, similar to that with 1a, reported earlier.While similar perchloric acid catalyzed reaction of 2b and 13a,b with trimethyl orthoformate gives the dienones 3b and 15a,b, the respective p-methoxystyrenoid derivatives 1c and 13c under identical conditions lead to the bicyclooctanones 22 and 23.Unlike the aforementioned 2-methyl 2-acetyl substrates, the desmethyl ketones 18a,b and 20 and the respective β-diethoxyethyl derivatives 24a,b and 25 on reaction with triethyl orthoformate and perchloric acid give only the respective bridged cyclodienones 26a,b and 27 in good yield.Similarly, perchloric acid catalyzed reactions of β-diethoxyethyl ketones 31a-d derived from 1-acetyl-4-arylcyclohex-3-enes (30a-d) in the presence or absence of triethyl orthoformate lead to the respective 6-arylbicyclonona-3,6-dien-2-ones (32a-d).The carbonyl conjugated double bond in the dienones 3a-c, 15a-d, and 32c,d undergoes chemoselective catalytic hydrogenation using piperidine and palladium-charcoal, affording the respective enones 4a-c, 16a-c, and 33c,d.
A Highly Efficient Synthesis of Functionalised Bridged-Cycloalkenones from γ,δ-Unsaturated Methyl Ketones by a Modified Formylation-Cyclisation Route
Gupta, Ratna Das,Brindaban, Ranu C.,Ghatak, Ushua Ranjan
, p. 619 - 620 (2007/10/02)
A highly efficient route to some aryl substituted bicyclononadienones from the correspnding γ,δ-unsaturated methyl ketones through perchloric acid-catalysed cyclisation of the intermediate α-(diethoxymethyl)ketones is described.A direct evidence in
